Re: ASPM allele origin dated to Adam's time

On Thu, 20 Oct 2005 17:12:14 +0200 Peter Ruest <pruest@mysunrise.ch>
writes:
>
> Hi, all
>
> I just read a recent News article about human evolution: M. Balter,
> "Are human
> brains still evolving? Brain genes show signs of selection", Science
> 309 (2005),
> 1662-1663. My quotations in the following are from Balter's
> comments. Two
> studies "led by human geneticist Bruce Lahn of the University of
> Chicago"
> [Science 309 (9 Sept. 2005), p. 1717 and 1720] "conclude that two
> genes thought
> to regulate brain growth have continued to evolve under natural
> selection until
> very recently". I haven't yet read the two original articles, but
> wanted to ask
> for your comments now.
>
> "Lahn's group focused on two genes, ... microcephalin and ASPM",
> mutations in
> which "cause microcephaly, in which the brain is severely reduced in
> size." Both
> genes "have come under strong natural selection since the
> chimp-human split" ~6
> Ma ago. Sequencing the two genes in 90 human cell lines provided
> "evidence that
> selection had operated on [them] much more recently - since the rise
> of modern
> humans." For both genes, one of their alleles occurs at
> "surprisingly high
> frequency ... unlikely to be due to random genetic drift or
> population migration".
>
> In this way, the origin of the favored microcephalin allele has been
> dated "at
> 37,000 years ago (with confidence intervals ranging from 14,000 to
> 60,000 years)
> - about the time of the explosion of symbolic behavior in Europe."
> Might this
> correspond to the time when humans were created in God's image
> (Gen.1:27)?
>
> ASPM stands for "abnormal spindle-like microcephaly associated" [J.
> Zhang,
> "Evolution of the human ASPM gene, a major determinant of brain
> size", Genetics
> 165 (2003), 2063-2070]. Two years ago, Zhang suggested that ASPM's
> positive
> selection had occurred earlier than 100,000 years ago and was
> connected with the
> human brain expansion between ~2 and ~0.3 My ago.
>
> n's new study suggests the allele of the ASPM gene prevalent today
> "arose
> 5800 years ago (with a possible range of 500 to 14,100 years), just
> before
> cities arose in the Near East." This sounds suspiciously close to
> the time for
> Adam, as deduced from the cultural indications of the early Genesis
> chapters.
>
> "Lahn's team argues that in the case of ASPM in particular, the
> young age of the
> selected allele and its worldwide distribution suggests that it was
> subject to a
> strong «selective sweep» in the very recent past. Lahn says these
> alleles may
> have provided an adaptive advantage, possibly although not
> necessarily
> cognition." An advantage in cognition arising this recently sounds
> preposterous.
>
> I don't expect any scientific proof of these two fixpoints in the
> biblical
> account on human origins - Gen.1:27 and 2:7 -, but there might be a
> good
> complementarity. What's your opinion?
>
> Peter
>
> --
> Dr. Peter Ruest, CH-3148 Lanzenhaeusern, Switzerland
> <pruest@dplanet.ch> - Biochemistry - Creation and evolution
> "..the work which God created to evolve it" (Genesis 2:3)
>
Peter,
I read the article. As a total layman in the area, I thought it gave
solid evidence. As is always the case, the dates have large standard
deviations, so there are various possible applications or
interpretations. However, since not all humans have the same gene,
perhaps there are the more human and the less human, or perhaps those
that look human but are not quite human. I may not be interpreting
matters correctly, but I strongly suspect that I don't want to go there.
On the other hand, the evidence fits clearly with change in /Homo sapiens
sapiens/. The species did not become unalterable 7000, 50,000 or whatever
years ago.
Dave
Received on Thu Oct 20 14:21:58 2005